I will use the “epidemic" model [1]}[2]} to describe the scrambling properties of SYK. We consider \(N\)  qubits where all the qubits are initially healthy. One extra “sick" qubit is added to the system at time \(\tau =0.\)  At time \(\tau =1\)  the qubits randomly come together in groups of \((q-1),\)  and if one in the group is sick the rest in that group become sick. In the next round the qubits are randomly regrouped into groups of \((q-1)\)  and again meet at time \(\tau =2.\)  Obviously the epidemic grows. The “size" of the epidemic at time \(\tau \)  is called \(\sigma (\tau ).\)  It is defined to be the number of sick qubits at time \(\tau \) . The fraction of the qubits which are sick is \(P(\tau ).\)  The relation between \(P\)  and \(\sigma \)  is,
\(\sigma = N P.\) 
